Probably better to post in the github issue rather than replying here.
ActivityPub can’t evolve? Is there some insurmountable technical blocker?
I suspected this would be an issue and have avoided voting on controversial posts. But if everyone did as I do, there would be no open discussions about pressing topics.
It is possible that ActivityPub could add this feature. But it’s not certain you’d even want that. Private votes would mean private for admins and mods too, so no more analyzing votes to look for down vote bots or manipulation or down vote brigading and all that stuff. Votes could lose all meaning. Admins and mods are unlikely to say goodbye to those moderation tools.
Even if it could be added, it’s probably years away.
Pseudonymous voting doesn’t mean a unique ID for every vote. It just means the user string itself is tokenized. You can still ban participation for that token without revealing the actual user. Literally the only thing this stops is easily seeing users who use the same name across several instances.
If the token is the same for the user across different posts, it would be easy to figure out who is actually behind the token by correlating voting patterns.